I've checked out the how to's and why for's and listened/read all the hubub about piston design and theory.
I think it's high time for this old fart to make an attempt at this bombastic fascination with this valve design.
My big thing, though, is, after reading through all the pages and pages of info all over the place(and here I come back to, to ask this) I'd like to know from the reputable know-abouts here which design scenario is best...I won't lie, I'm thinking about a gb shooter with probably a hopper of some sort for a semi-auto firing capacity to be ran off my big industrial compressor out in the garage with a 150 gal tank that I used to haul to the jobsites on a trailer when I was doing several houses at a time. It's old but well taken care of. my wife says it eats more electricity than it ever did gas when it was gas...so now I'm sitting around reminiscing and tryimg to think of a way to show her how useful it still is... I told my oldest son about my idea and showed him some prelim drawings of what I envision ... I thought he was going to hyperventilate! One problem off the bat may be the fact that we don't have our big lot anymore to play around with this kind of thing so much, granted it's still on the trailer, just sitting on the blocks w/out tires... and plugged in. None-the-less, I still want to build this thing and now, after seeing this beast that Big Ed has put together, I know we can make this happen.
So help me out here guys, help me save ol' green from the chopping block and come up with a design capable of flinging golf balls as quickly as possible w/ a 150 gal tank behind it or my wife will sell it off seeing as how she's already gone and talked to a shop out in the valley about buying it. She has always loved the tater guns and shooting and such as well as anyone else,I hope... or maybe I'm just kidding myself about the sentimentality of it...Imade a lot of money with it and built a lot of houses.It's been good to my family anda whole lotta other guys whose families were fed from its ferocity. Am I just grasping at a decomposing straw falling apart in my hand? I must either be crazy or ?

feral_patriot, Funny thing you mentioned a 150 gallon compressor.
I have a 100 gallon tank that I am going to use for a Trailered cannon. Since it would suck even a big 50lbs CO2 tank dry in 4+ shots. I'm going to use a Atlas diesel air compressor (used for jack-hammering) to feed it. I'm thinking pumpkins - 10" barrel and a 11" piston, all steel. Maybe sometime in 2009...

Here's a 1.5" asco valve with a 15 gallon tank.
"Mini-Pak" - Long-range tennis baller. I have 7' barrel on it now. (Crummy weather have not test fired yet.)